1. Field of the Invention
The invention relates to a sheet-fed scanner capable of scanning multiple scan lines for image signal calibration, and more particularly to a sheet-fed scanner capable of scanning multiple scan lines on a calibration sheet for image signal calibration.
2. Description of the Related Art
Typically, before scanning a document, a scanner has to scan a calibration sheet with a standard color, such as the standard white, the standard black or the like, to obtain a calibration standard for calibrating an image signal of the document.
In the conventional sheet-fed scanner, the stationary scanning module scans the document fed by the sheet-feeding mechanism as well as the stationary calibration sheet. Therefore, when the scanning module is scanning the calibration sheet, the data of only one scan line can be obtained as the calibration standard for the subsequent scanning process. If the calibration sheet is contaminated, the data of the single scan line may be flawed, which would greatly influence the subsequent scanning result.
Thus, providing a sheet-fed scanner capable of scanning multiple scan lines as the calibration standard for the image signal of the document without distorting the calibrated image is an important object to be achieved by the invention.